Design rules for minimizing voltage losses in high-efficiency organic solar cells
Source abstract
Abstract
The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor-acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor-acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Organic Electronics and Photovoltaics · Perovskite Materials and Applications · Conducting polymers and applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (58)
Show source-provided references
1. Yu, G., Gao, J., Hummelen, J. C., Wudl, F. & Heeger, A. J. Polymer photovoltaic cells: enhanced efficiencies via a network of internal donor–acceptor heterojunctions. Science 270, 1789–1791 (1995).10.1126/science.270.5243.1789 ↗
2. Gelinas, S. et al. Ultrafast long-range charge separation in organic semiconductor photovoltaic diodes. Science 343, 512–516 (2014).10.1126/science.1246249 ↗
3. Park, S. H. et al. Bulk heterojunction solar cells with internal quantum efficiency approaching 100%. Nat. Photon. 3, 297–302 (2009).10.1038/nphoton.2009.69 ↗
4. He, Z. et al. Single-junction polymer solar cells with high efficiency and photovoltage. Nat. Photon. 9, 174–179 (2015).10.1038/nphoton.2015.6 ↗
5. Vandewal, K. et al. Quantification of quantum efficiency and energy losses in low bandgap polymer:fullerene solar cells with high open-circuit voltage. Adv. Funct. Mater. 22, 3480–3490 (2012).10.1002/adfm.201200608 ↗
6. Yao, J. et al. Quantifying losses in open-circuit voltage in solution-processable solar cells. Phys. Rev. Appl. 4, 014020 (2015).10.1103/PhysRevApplied.4.014020 ↗
7. Green, M. A. Radiative efficiency of state-of-the-art photovoltaic cells. Prog. Photovolt. 20, 472–476 (2012).10.1002/pip.1147 ↗
8. Vandewal, K., Tvingstedt, K., Gadisa, A., Inganäs, O. & Manca, J. V. Relating the open-circuit voltage to interface molecular properties of donor:acceptor bulk heterojunction solar cells. Phys. Rev. B 81, 125204 (2010).10.1103/PhysRevB.81.125204 ↗
9. Burke, T. M., Sweetnam, S., Vandewal, K. & McGehee, M. D. Beyond Langevin recombination: how equilibrium between free carriers and charge transfer states determines the open-circuit voltage of organic solar cells. Adv. Energy Mater. 5, 1500123 (2015).10.1002/aenm.201500123 ↗
10. Chen, X.-K., Ravva, M. K., Li, H., Ryno, S. M. & Brédas, J.-L. Effect of molecular packing and charge delocalization on the nonradiative recombination of charge-transfer states in organic solar cells. Adv. Energy Mater. 6, 1601325 (2016).10.1002/aenm.201601325 ↗
11. McGlynn, S. P. Energetics of molecular complexes. Chem. Rev. 58, 1113–1156 (1958).10.1021/cr50024a004 ↗
12. Li, W., Hendriks, K. H., Furlan, A., Wienk, M. M. & Janssen, R. A. J. High quantum efficiencies in polymer solar cells at energy losses below 0.6 eV. J. Am. Chem. Soc. 137, 2231–2234 (2015).10.1021/ja5131897 ↗
13. Menke, S. M. et al. Limits for recombination in a low energy loss organic heterojunction. ACS Nano 10, 10736–10744 (2016).10.1021/acsnano.6b06211 ↗
14. Kawashima, K., Tamai, Y., Ohkita, H., Osaka, I. & Takimiya, K. High-efficiency polymer solar cells with small photon energy loss. Nat. Commun. 6, 10085 (2015).10.1038/ncomms10085 ↗
15. Liu, J. et al. Fast charge separation in a non-fullerene organic solar cell with a small driving force. Nat. Energy 1, 16089 (2016).10.1038/nenergy.2016.89 ↗
16. Baran, D. et al. Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages. Energy Environ. Sci. 9, 3783–3793 (2016).10.1039/C6EE02598F ↗
17. Hou, J. H., Inganas, O., Friend, R. H. & Gao, F. Organic solar cells based on non-fullerene acceptors. Nat. Mater. 17, 119–128 (2018).10.1038/nmat5063 ↗
18. Rau, U. Reciprocity relation between photovoltaic quantum efficiency and electroluminescent emission of solar cells. Phys. Rev. B 76, 085303 (2007).10.1103/PhysRevB.76.085303 ↗
19. Kirchartz, T., Taretto, K. & Rau, U. Efficiency limits of organic bulk heterojunction solar cells. J. Phys. Chem. C 113, 17958–17966 (2009).10.1021/jp906292h ↗
20. Benduhn, J. et al. Intrinsic non-radiative voltage losses in fullerene-based organic solar cells. Nat. Energy 2, 17053 (2017).10.1038/nenergy.2017.53 ↗
21. Miller, O. D., Yablonovitch, E. & Kurtz, S. R. Strong internal and external luminescence as solar cells approach the Shockley-Queisser limit. IEEE J. Photovolt. 2, 303–311 (2012).10.1109/JPHOTOV.2012.2198434 ↗
22. Zhang, H. et al. Fullerene-free polymer solar cell based on a polythiophene derivative with an unprecedented energy loss of less than 0.5 eV. J. Mater. Chem. A 4, 18043–18049 (2016).10.1039/C6TA07672F ↗
23. Kawashima, K., Osaka, I. & Takimiya, K. Effect of chalcogen atom on the properties of naphthobischalcogenadiazole-based π-conjugated polymers. Chem. Mater. 27, 6558–6570 (2015).10.1021/acs.chemmater.5b03124 ↗
24. Liao, S. H., Jhuo, H. J., Cheng, Y. S. & Chen, S. A. Fullerene derivative-doped zinc oxide nanofilm as the cathode of inverted polymer solar cells with low-bandgap polymer (PTB7-Th) for high performance. Adv. Mater. 25, 4766–4771 (2013).10.1002/adma.201301476 ↗
25. Duan, R. et al. Application of two-dimensional conjugated benzo[1,2-b:4,5-b′]dithiophene in quinoxaline-based photovoltaic polymers. Macromolecules 45, 3032–3038 (2012).10.1021/ma300060z ↗
26. Chen, S. et al. A wide-bandgap donor polymer for highly efficient non-fullerene organic solar cells with a small voltage Lloss. J. Am. Chem. Soc. 139, 6298–6301 (2017).10.1021/jacs.7b01606 ↗
27. Lin, Y. et al. An electron acceptor challenging fullerenes for efficient polymer solar cells. Adv. Mater. 27, 1170–1174 (2015).10.1002/adma.201404317 ↗
28. Holliday, S. et al. High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor. Nat. Commun. 7, 11585 (2016).10.1038/ncomms11585 ↗
29. Baran, D. et al. Reducing the efficiency–stability–cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells. Nat. Mater. 16, 363–369 (2017).10.1038/nmat4797 ↗
30. Zhao, W. et al. Molecular optimization enables over 13% efficiency in organic solar cells. J. Am. Chem. Soc. 139, 7148–7151 (2017).10.1021/jacs.7b02677 ↗
31. Dai, S. et al. Fused nonacyclic electron acceptors for efficient polymer solar cells. J. Am. Chem. Soc. 139, 1336–1343 (2017).10.1021/jacs.6b12755 ↗
32. Perez, M. D., Borek, C., Forrest, S. R. & Thompson, M. E. Molecular and morphological influences on the open circuit voltages of organic photovoltaic devices. J. Am. Chem. Soc. 131, 9281–9286 (2009).10.1021/ja9007722 ↗
33. Potscavage, W. J., Sharma, A. & Kippelen, B. Critical interfaces in organic solar cells and their influence on the open-circuit voltage. Acc. Chem. Res. 42, 1758–1767 (2009).10.1021/ar900139v ↗
34. Goris, L. et al. Observation of the subgap optical absorption in polymer–fullerene blend solar cells. Appl. Phys. Lett. 88, 052113 (2006).10.1063/1.2171492 ↗
35. Tvingstedt, K. et al. Electroluminescence from charge transfer states in polymer solar cells. J. Am. Chem. Soc. 131, 11819–11824 (2009).10.1021/ja903100p ↗
36. Vandewal, K., Tvingstedt, K., Gadisa, A., Inganäs, O., & Manca, J. V. On the origin of the open-circuit voltage of polymer–fullerene solar cells. Nat. Mater. 8, 904–909 (2009).10.1038/nmat2548 ↗
37. Dimitrov, S. D. & Durrant, J. R. Materials design considerations for charge generation in organic solar cells. Chem. Mater. 26, 616–630 (2014).10.1021/cm402403z ↗
38. Abbaszadeh, D. et al. Elimination of charge carrier trapping in diluted semiconductors. Nat. Mater. 15, 628–633 (2016).10.1038/nmat4626 ↗
39. Wall, M. E., Rechtsteiner, A. & Rocha, L. M. in A Practical Approach to Microarray Data Analysis (eds Berrar, D. P., Dubitzky, W. & Granzow, M.) 91–109 (Kluwer, Norwell, MA, 2003).
40. Stoltzfus, D. M. et al. Charge generation pathways in organic solar cells: assessing the contribution from the electron acceptor. Chem. Rev. 116, 12920–12955 (2016).10.1021/acs.chemrev.6b00126 ↗
41. Bässler, H. & Köhler, A. ‘Hot or cold’: how do charge transfer states at the donor–acceptor interface of an organic solar cell dissociate? Phys. Chem. Chem. Phys. 17, 28451–28462 (2015).10.1039/C5CP04110D ↗
42. Deibel, C. & Dyakonov, V. Polymer–fullerene bulk heterojunction solar cells. Rep. Prog. Phys. 73, 096401 (2010).10.1088/0034-4885/73/9/096401 ↗
43. Grancini, G. et al. Hot exciton dissociation in polymer solar cells. Nat. Mater. 12, 29–33 (2013).10.1038/nmat3502 ↗
44. Jailaubekov, A. E. et al. Hot charge-transfer excitons set the time limit for charge separation at donor/acceptor interfaces in organic photovoltaics. Nat. Mater. 12, 66–73 (2013).10.1038/nmat3500 ↗
45. Savoie, B. M. et al. Unequal partnership: asymmetric roles of polymeric donor and fullerene acceptor in generating free charge. J. Am. Chem. Soc. 136, 2876–2884 (2014).10.1021/ja411859m ↗
46. Weu, A. et al. Field-assisted exciton dissociation in highly efficient PffBT4T-2OD: fullerene organic solar cells. Chem. Mater. 30, 2660–2667 (2018).10.1021/acs.chemmater.8b00094 ↗
47. Bixon, M., Jortner, J. & Verhoeven, J. W. Lifetimes for radiative charge recombination in donor–acceptor molecules. J. Am. Chem. Soc. 116, 7349–7355 (1994).10.1021/ja00095a044 ↗
48. Vandewal, K., Tvingstedt, K. & Inganäs, O. Polarization anisotropy of charge transfer absorption and emission of aligned polymer: fullerene blend films. Phys. Rev. B 86, 035212 (2012).10.1103/PhysRevB.86.035212 ↗
49. Yao, H. et al. Design and synthesis of a low bandgap small molecule acceptor for efficient polymer solar cells. Adv. Mater. 28, 8283–8287 (2016).10.1002/adma.201602642 ↗
50. Snaith, H. The perils of solar cell efficiency measurements. Nat. Photon. 6, 337–340 (2012).10.1038/nphoton.2012.119 ↗
51. Hirata, S. & Head-Gordon, M. Time-dependent density functional theory for radicals—an improved description of excited states with substantial double excitation character. Chem. Phys. Lett. 302, 375–382 (1999).10.1016/S0009-2614(99)00137-2 ↗
52. Grimme, S., Antony, J., Ehrlich, S. & Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 132, 154104 (2010).10.1063/1.3382344 ↗
53. Stewart, J. J. P. Optimization of parameters for semiempirical methods VI: more modifications to the NDDO approximations and re-optimization of parameters. J. Mol. Model. 19, 1–32 (2013).10.1007/s00894-012-1667-x ↗
54. Barbara, P. F., Meyer, T. J. & Ratner, M. A. Contemporary issues in electron transfer research. J. Phys. Chem. 100, 13148–13168 (1996).10.1021/jp9605663 ↗
55. Cave, R. J. & Newton, M. D. Generalization of the Mulliken–Hush treatment for the calculation of electron transfer matrix elements. Chem. Phys. Lett. 249, 15–19 (1996).10.1016/0009-2614(95)01310-5 ↗
56. Frisch, M. J. et al. GAUSSIAN09 (Gaussian, Inc., 2009).
57. Frisch, M. J. et al. Gaussian 16 Revision A. 03. 2016 (Gaussian, Inc., 2016).
58. Shao, Y. et al. Advances in methods and algorithms in a modern quantum chemistry program package. Phys. Chem. Chem. Phys. 8, 3172–3191 (2006).10.1039/B517914A ↗